/Engine/Source/Runtime/Engine/Public/SceneManagement.h
Draw an opaque line. The alpha component of Color is ignored.
void DrawLine ( const FVector & Start, const FVector & End, const [FLinearColor](API\Runtime\Core\Math\FLinearColor) & Color, uint8 DepthPriorityGroup, float Thickness, float DepthBias, bool bScreenSpace )